Problem: Simplify the following expression: $k = \dfrac{10fh - 20h^2}{10h^2} - \dfrac{10gh}{10h^2}$ You can assume $f,g,h \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{10fh - 20h^2 - (10gh)}{10h^2}$ $k = \dfrac{10fh - 20h^2 - 10gh}{10h^2}$ The numerator and denominator have a common factor of $10h$, so we can simplify $k = \dfrac{f - 2h - g}{h}$